Deep-drawable plastic composite comprising plastic film on fibrous support

ABSTRACT

Deep-drawable composite comprising: A. A PLASTIC FILM OF DEEP-DRAWABLE PLASTIC, B. A NON-WOVEN FLEECE CONSISTING ESSENTIALLY OF DRAWABLE FILAMENTS WHICH ARE DRAWABLE UPON DEEP-DRAWING OF THE PLASTIC FILM, C. SAID PLASTIC FILM COATING SAID FLEECE. The composite and process of producing it are claimed.

United States Patent Hartmann Nov. 12, 1974 1 DEEP-DRAWABLE PLASTIC COMPOSITE [56] References Cited I COMPRISING PLASTIC FILM ON FIBROUS UNITED STATES PATENTS SUPPORT 2,715,591 8/1955 Graham l6l/D1G. 2 [75] Inventor; Ludwig Hartman 3,158,525 1l/1964 Reynolds 161/170 Oberflockenbach, Germany OTHER PUBLICATIONS 1 1 Assigneel Carl Freudenberg, Weinheim, R. w. Moncrieff, Man-Made Fibres, 1963, pp. 11-12,

Germany 89, 91.

[22] Filed: Jan. 15, 1970 Primary ExaminerMari0n E. McCamish [21] Appl' 3129 Attorney, Agent, or FirmJohnst0n, Keil, Thompson Related US. Application Data & Shurtleff [62] Division of Ser. No. 514,026, Dec. 15, 1965, Pat. No.

3,523,149. [57] ABSTRACT v Deep-drawable composite comprising: [30] Forelgn Apphcatmn Pnomy Data 21. a plastic film 0f deep-drawable plastic,

Dec. 23, Germany 1.: a non woven fleece consisting essentially of drawable filaments which are drawable upon U-S. A, deep d 'awing of the piastic l6l/DIG- 2 c. said plastic film coating said fleece. The Int. Cl. composite and process of producing are [58] Field of Search 161/170, 256, DIG. 2; Claimeci DEEP-DRAWING WITHVACUUM 11 Claims, 4 Drawing Figures Pmmwu I 21914 I SL847. 729

F IG. 2.

INVENTOR LUDWIG HART MANN ATTORNEYS.

DEEP-DRAWABLE PLASTIC COMPOSITE COMPRISING PLASTIC FILM ON FIBROUS SUPPORT This application is a division of application Ser. No. 514,026, filed Dec. 15, 1965, now US. Pat. No. 3,523,149.

The plastic forming of artificial leather and coatings is done most conveniently by the deep-drawing of thermoplastic sheets. The disadvantages of the products manufacture in this manner lies, for one thing, in their poor thermal shape stability, since the sheet which has once been formed by the action of heat can be deformed again in precisely the samemanner by another exposure to heat. Furthermore, these unreinforced sheets have an unsatisfactory tearing strength and resistance to continued tearing, as well as other disadvantageous mechanical properties. An improvement has been contributed in this regard by sheet materials supported, for example, by knit goods which could stretch to a certain extent on account of their mesh structure. It is a principal object of the instant invention to provide further improvements in this area.

According to the invention, adeep-drawn composite comprising a plastic film and a film support therefor is produced by coating a non-woven fleece comprising drawable filaments with a deep-drawable plastic, and deep-drawing the coated plastic to thereby deep-draw the plastic and draw the drawable fibers and form said composite.

In a preferred embodiment of the invention, the drawable filaments are continuous monofilaments, de-

fleece.

The filaments formed by gas stream, or air stream drawing, are partially drawn during the forming therof, and'remain further drawable, so that additional drawing occurs during the deep-drawing of the fleece coated with drawable plastic.

Though not a preferred embodiment, instead of drawable filaments, afleece composed of undrawn staple fibers bonded together with an elastic bonding agent rendering the fleece so that it can be irreversibley elongated during drawing, can be used. In the case of extensive deep-drawing, however, difficulties have occurred because, as a result of the short fiber lengths, the fibers become loose and overstretching or tears occurs. Furthermore, the undrawn filaments tend to become brittle when stored.

By the process of the invention, especially where drawable, fibers are used, the prior art difficulties are overcome and it is possible to produce artificial leather amenable to deep-drawing and having good thermal shape stability and high strength characteristics.

A batt of continuous filaments can be prepared by the spinning of fiber-forming high polymers,'the filaments being slightly but not fully drawn with air. This produces a partial orientation of the filamentary molesirably produced by gas stream drawing, for example by cules, the result being that, due to the adequate magnitude of the intermolecular forces, the filaments are stable during storage, but are still ductile since they have not been fully drawn. Filaments are preferably used which have elongation-to-breakage between and 400%. To achieve fiber batts of great uniformity, spin- However, other appropriate apparatus can be used for the purpose, as long as the principle is preserved that the filaments are carried away from the spinnerets in straight ranks, preferably with the aid of streaming gases, and remain separate from one another for a distance of, for example, 600 mm, up to the moment of formation of the batt. In this manner the best possible distribution of the filaments is assured a fact which is of great importanceto the ability of the product to be uniformly shaped afterwards. In the manufacture of classical batts from short fibers, clumping of fibers cannot be avoided, and results in areas of various density, which manifests itself in the plastic shaping or deepdrawing in the form of thin spots and tears.

The spinning of ranks of adjacent filaments and drawing them by means of air streams applied from both sides also has the advantage of identical treatment of the linearly co-adjacent filaments. In this manner, both the drawing conditions and the cooling conditions can be made substantially identical for all filaments. The latter is of importance inasmuch as the cooling also assures the freezing of the molecular orientation 'that has been achieved by the drawing forces on the molten filaments. The manufacture of the above-mentioned fiber fleeces can be'performed, for example, by means of the process and apparatus described in application Ser. No. 341,489, filed Jan. 27, 1964. After the batt or fleece has been formed, the filaments in the fleece can be adhered togetherat isolated points. This can be performed, for example, by autogenous solidification by making the fiber. surface sticky or with the aid of secondary bonding agents, such as by treatment with rubber or plastic dispersions or solutions.

Thereafter the fleece thus formed can be subjected to a laminating or coating process in order to produce the plastic or artificial leather surface. For example, a PVC sheet is made by calendering by prior art methods. This sheet is coated with a sticky PVC pasteand the fleece manufactured by the above process is laminated to itby means of a press. Simultaneously with the laminating process, which is performed preferably along with the application of heat, the surface of the PVC sheet can be embossed. The PVC coating'c'analso be applied by brushing or rolling it on. In addition to PVC or plasticized PVC mixtures, other film-forming high polymers can of course be used, such as polyurethanes, for example, for the manufacture of the artificial leather surface. It is important in any case that the deep-drawability of the sheet material and the fiber fleece be matched to one another so that both the fleece filaments and the plastic coating are drawn (irreversibly elongated) during the deep-drawing operation. The same is true especially in regard to the temperature range in which deep-drawability occurs, ie the temperature should be such that the required drawing will occur. This can be varied in the case of the fleece by the degree of draft given to the filaments and by the nature of the polymer which is used for the manufacture of the filaments. Polyamides, polypropylene, polyurethanes and polyesters have thus far proven good in this application. Thermoplastic fibers in general can be used. Another factor is the nature of the bond which is used in adhering the filaments to one another. A preferred embodiment consists in bonding the filaments by means of a binding agent which can simultaneously serve as a binding agent between the filaments and the sheet material. Accordingly, a binder adhesive with respect to the plastic sheet is desirable.

The invention is further described in reference to the accompanying drawing, wherein:

FIG. 1 depicts the forming of a deep-drawable artificial leather composite 6: a plastic sheet 1 and a nonwoven fleece 2 having a plastisol or adhesive film 4 applied at 3, are calendered together by the rolls 5, to provide the composite 6 composed of plastic coating 6a and non-woven fiber fleece support 6b;

FIG. 2 shows schemetically the heating of the fleece to condition it for deep drawing: the composite 6 is passed through an infrared radiator comprising an upper heating bank 7 and a lower heating bank 8;

FIG. 3 shows the composite on a deep-drawing, vacuum device: the composite is formed into shaped structure 9 by vacuum drawing on the vacuum drawing device 10; and

FIG. 4 shows the shaped structure 9 removed from the deep-drawing device.

While the invention has been described with respect to particular embodiments thereof, these embodiments are merely representative and do not serve to define the limits of the invention.

The following example illustrates an embodiment of this kind, though it is not to be interpreted as a restriction as regards the chemical combinations.

EXAMPLE Polycaprolactam (extract content 0.4, n red 2.27) was spun out of a spinning device which consisted of 12 adjacent spinnerets of the kind described in the example (page 9) of the application Ser. No. 430,092, filed Feb. 3, 1965. 1.5 normal cubic meters per minute of air at 235 C. were pumped in per spinneret (spinneret temperature, 240 C.) and ejected from two slits 0.3 mm wide and at a distance of 0.4 mm on both sides of the row of spinneret holes, in the fiber spinning direction. The row of filaments emerging from each spinneret was fed together with the air streams enveloping it on both sides into a guiding channel 40 mm away, in the manner represented in FIG. 3 of said application Ser. No. 430,092. This resulted at the lower end of the 600 mm long passage in an air velocity in the passage itself of 1,000 meters per minute at a temperature of 60 C. At a pumping speed of 0.1 cc per spinneret hole of 400 microns diameter, filaments were obtained with the following properties:

1 denier 3.5 grams per denier 170% elongation to breakage By aspiration onto a continuously moving wire screen running at a speed of 2.5 m/min, a fiber batt was obtained weighing 60 grams per square meter of area. This batt was imbibed by means of an impregnating mechanism with a 20% dispersion of a butadiene acrylonitrile polymer containing 4 copolymerized acrylic acid. After drying, a binding agent absorption of 60 g/m was obtained.

This batting was laminated at a temperature of to a PVC calender sheet plasticized by means of 30% of a copolymeric butadiene acrylonitrile styrene plasticizer and 20% dioctylphthalate, making use of a PVC plastisol. The weight of the sheet amounted to 600 grams per square meter, and that of the PVC plastisol adhesive was 50 g/m The laminate thus manufactured was outstandingly well suited for deep-drawing by vacuum forming, the PVC side of the laminate being advantageously warmed to about 140 and the fiber batt side to about prior to forming.

What is claimed is:

l. Deep-drawable composite comprising:

a. a plastic film of deep-drawable plastic,

b. a non-woven fleece consisting essentially of partially drawn and further drawable filaments which are drawable upon deep-drawing of the plastic film,

c. said plastic film coating said fleece.

2. Composite according to claim 1, said drawable filaments being continuous monofilaments.

3. Composite according to claim 2, said drawable filaments having an elongation to breakage of about 100400%.

4. Composite according to claim 1, said filaments being bonded together with a binding agent.

5. Composite according to claim 4, said binder being adhesive with respect to the plastic coating and bonding the coating to the fleece.

6. Composite according to claim 1, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide, polypropylene, polyurethane or polyester polymers.

7. Composite according to claim 1, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide polymers.

8. Deep drawable composite comprising:

a. a plastic film of deep-drawable plastic,

b. a non-woven fleece consisting essentially of randomly disposed partially drawn and further drawable continuous monofilaments formed by gas stream drawing and collected to form the nonwoven fleece, said continuous monofilaments having an elongation to breakage of about 100400%, and being bonded together with a binding agent,

c. said plastic coating said fleece.

9. Composite according to claim 8, said binder being adhesive with respect to the plastic coating and bonding the coating to the fleece.

10. Composite according to claim 8, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide, polypropylene, polyurethane or polyester polymers.

11. Composite according to claim 8, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide polymers. 

1. DEEP-DRAWABLE COMPOSITE COMPRISING: A. A PLASTIC FILM DEEP-DRAWABLE PLASTIC, B. A NON-WOVEN FLEECE CONSISTING ESSENTIALLY OF PARTIALLY DRAWN AND FURTHER DRAWABLE FILAMENTS WHICH ARE DRAWABLE
 2. Composite according to claim 1, said drawable filaments being continuous monofilaments.
 3. Composite according to claim 2, said drawable filaments having an elongation to breakage of about 100-400%.
 4. Composite according to claim 1, said filaments being bonded together with a binding agent.
 5. Composite according to claim 4, said binder being adhesive with respect to the plastic coating and bonding the coating to the fleece.
 6. Composite according to claim 1, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide, polypropylene, polyurethane or polyester polymers.
 7. Composite according to claim 1, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide polymers.
 8. Deep drawable composite comprising: a. a plastic film of deep-drawable plastic, b. a non-woven fleece consisting essentially of randomly disposed partially drawn and further drawable continuous monofilaments formed by gas stream drawing and collected to form the non-woven fleece, said continuous monofilaments having an elongation to breakage of about 100-400%, and being bonded together with a binding agent, c. said plastic coating said fleece.
 9. Composite according to claim 8, said binder being adhesive with respect to the plastic coating and bonding the coating to the fleece.
 10. Composite according to claim 8, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide, polypropylene, polyurethane or polyester polymers.
 11. Composite according to claim 8, said plastic being polyurethane or polyvinylchloride plastic, said filaments being polyamide polymers. 